Process for the preparation of vita



Patented Aug. 22, 1944 PRocEss FOR THE PREPARATION oFvr-rA- MIN B1 AND OF SIMILARLY BUILT COM- 'Po.UNns,'

Rezsd Kiinig, Arpad Gerecs, andj zoltan Fiildi, Budapest, Hunga y; rested .in the Alien .Property Custodian No Drawing. Application April 24, 1941, Serial .No. 390,124. In Hungary May 25, .1940

7 Claims.

The present invention relates to a new process for preparing vitamin B1 and compounds of similar structure. This process consists in subjecting a member of the group consisting of 'yaceto-v-halogen-propyl alcohol [its cyclic form, ethers of the cyclic form, semi-cyclic form of 'yaceto-v-halogen-propyl alcohol] to the action of reagents generally used for replacirg an alcoholic hydroxyl group with a halogen atom and in subjecting the Z-methyl-2,3-dihalogen-tetrahydrofurane, thus obtained, to the action of 2- alkyl 4 amino 5 ithioform amido-alkyllpyrimidines.

A preferred form of the invention consists in subjecting a member of the group consisting of 'y-aceto-v-chloro-propyl alcohol Tits cyclic form,

ethers of the cyclic form, semi-cyclic form' of the -aceto-v-chloro propyl alcohol] to the action of reagents generally used for replacing a hydroxyl group with a chlorine atom and in subjecting the 2-methy'l-2,3-dichloro-tetrahydrofurane, thus obtained, to the action of 2-methyl-4-a'mino-5- [thioformamidomethyll-pyrimidine. One may further proceed in subjecting reaction mixtures containing'one or more members of the group consisting of aceto-v-chloro-propyl alcohol, its cyclic form, its semi-cyclic form, an ether of the cyclic form of the 'y-aceto'y-chloro-propyl alcohol, to the action of hydrochloric acid and in subjecting the 2 methyl-2,3-dichloro tetrahydrofurane, thus obtained, to the action of 2-methyl-4-amino- 5- [thioformamido-alkyll-pyrimidine.

The action of the -2 -methyl-2,3-dihalogentetrahydrofurane on 2-alkyl-4-amino-5-[thioformamido-alkyl]-pyrimidine is preferably carried out in formic acid as reaction medium. One may use preferably an acid binding agent, such as tertiary bases Ipyridinel, or alkali salts of organic acids [e. g. potassium formate or sodium benzoate] which will bind the halogen acid, such as hydrochloric acid formed during the reaction.

Another object of the present invention is to provide for methods to prepare 2'-methyl-2,3-dichloro-tetrahydrofurane, which have been 1111- known till now. For this purpose one may subject 'y-aceto-v-chloro-propyl alcohol to the action of gaseous hydrogen chloride when the following compound is formed:

The v-aceto-y-chloro-propyl :alooholexists mainly-as described in the literature-in the cyclic form, this form being in a relation of desmotropy with the open chain form:

formula:

. ol.on onl cm.oo.onc1.cn=.cm-oo CH1 CH3 O as shown by Stevens and Stein in the Journ. of the Americ. Chem. Soc.,'vo1. 62, page 1045. All these parent components of the v-aceto-ychloro-propyl alcohol are capable of the same reaction with reagents generally used for replacing a hydroxyl group with a halogen group. There-- fore, all 'y-aceto-y-chloro-propyl alcohols obtained by the different methods to be found in the literature can be used as starting materials with the same good result and it is not necessary to separate the different parent constituents from each other. In the following, when 'y-aceto-vchloro-propyl alcohol is mentioned without further designation, the chemically pure 'y-aceto 'ychloro-propyl alcohol" itself, or the 'y-aceto-v chloro-propyl alcohol of a quality as described by Todds and Bergel [100. ,cit.], or as described by,

Buchman [100. cit.], or as described by Stevens and Stein [100. cit.], or mixtures thereof are to be meant. The experiments described have been effected with the same good results with the different types enumerated above.

The Z-methyl 2,3 dichloro-tetrahydrofurane can be prepared also by decarboxylating the aceto-chloro-butyrol actone with concentrated hydrochloric acid, saturating thereaction mixture with hydrogen chloride gas and removing the formed tetrahydrofurane-dichloro derivative. This dichloride can also beobtained by other methods, e. g. by subjecting aceto-chloro-propyl alcohol to the action of thionylchloride. The details of the preparation of the abovementioned product can be found in the following.

One proceeds by starting from aceto-chloropropyl alcohol as follows:

50 grams of aceto-chloro-propyl alcohol are saturatedwhile coolin'gin a refrigerated mixture grams of thionyl-chloride. One observes a rise in temperature and development of gas. The mixture is kept then for 1 hour at 50 and the excess of thionylchloride is distilled oifin the vacuo of a blast-pump. 'The residual oil is distilled in vacuo at a pressure of 0.5 mm. Hg Atthe temperature of about 39-43' 2.8 .g. of 2-methyl-2,3- dichloro-tetra-hydrofurane distills, which forms a colourless mobile liquid slightly fuming in the air. It contains about 43.5% of chlorine.

It can be prepared from aceto-chloro-butyrolactone in the following manner:

50 grams of aceto-chloro-butyrolactone and 25 com. of concentrated hydrochloric acid arestirred for.3 hours at 35. During this the formation of carbonic acid stops. mixture to 50 no remarkable formation of carbon'ic acid can be observed. Afterwards the.

mixture is cooled with a refrigerating mixture.

and saturated during three hours with hydrogen chloride gas. The obtained oil is taken up in chloroform driedwith dehydrated sodium sulfate, then the chloroform is removed and the residual oil is fractionated in vacuo at a pressureof 1 mm. Hg. One obtains 26.28 g. of 2- methyl-2,3-dichloro-tetrahydrofurane containing about 45% of chlorine.

The product can be obtained starting'from aceto-chloro-butyrolactonealso in the following manner: v i g It is mixed with about .1 mol. of water and is saturated at room temperature under stirring with hydrogen chloride gas. It is stirred until no formation of carbonic acid is observed. In the meantime the temperature can be raised to 35-40". Afterwards it is cooled in a refrigerating mixture, saturated with hydrogen chloride gas and shaken out with petroleum ether. After the removal of the petroleum ether the residual product is fractionated. The' fraction distilling at about 50 in vacuo at a pressure of 8 mm. Hg.

contains the 2-methyl-2,3-diclr1loro-tetrahydrofurane.

One may proceed starting from aceto-chlorobutyrolactone also as follows;

50 grams of aceto-chloro-butyrolactone and 6 ccm. of hydrochloric acid of volumetric percentage are stirred for several hours on-the water.

bath until thev end of the formation of carbonic then the solution is dried eventually with dehy drated sodium sulfate and after. removing the solvent the residualoilisfractionatedat a pres- By heating the the latter mentioned pyrimidine compound also 5 grams of the alcohol are pouredover with 5 better of 50.

homologous compounds can be used.

To 10 com. of formic acid of 91% first 7.7 grams of 2 methyl-2,3-dichloro-tetrahydrofurane, then under cooling in icewater 3.9 grams of pyridine are added. To this mixture 5 grams of Z-methyl- 4-amino- 5 [thioformamido-methyll pyrimidine are added. The temperature rises slightly and a crystalline compound precipitates, then the reaction mixture is kept for 40 hours in an incu- One obtains alight brown solution to which45 ccm. of absolute alcohol and 5 ccm. of absolute alcohol containing 30% of hydrogen chloride gas are added. After boiling the mixture, the vitamin B1 crystallizes in the form 'of white crystalline plates. The'mixture is kept for from one to two hours in ice-water, filtered by suction and washed with 20 ccm. of absolute alcohol. The product dried in vacuo weighs 4.5-5.3 grams and melts at about 240.

' In the foregoing example the pyridine was used as acid binding agent. In the following example the use of potassium formate is shown:

Under cooling and stirring to 2 com. of formic acid of about 1.5 grams of 2-methyl-2,3- dichloro-tetrahydrofurane,0.85 gram. of dry potassium formate in form of a fine powder and 1 gram of 2-methyl-4-amino-5-[thioformamidomethyl] pyrimidine are added, then the reaction.

mixture thus obtained is kept for 65 hours in an incubator of 50. Afterwards 9 com. of absolute alcoholand 1 com. of absolute alcohol containing 30% of hydrogen chloride gas-are added to the.reaction mixture which is then boiled. The.

crystals precipitating at cooling are filtered by suction after about an hour standing. The crystals are dissolved in water and 20 ccm. of a hot aqueous solution of 1.7 grams ammonium picrate are added. The obtained picrate is filtered, after a short standing, by suction, washed with water and dried in vacuo. One obtains about 2.3 grams of picrate having a melting point of 203-204". Then, the picrate is boiled in 20 com. of absolute alcohol, then 5 ccm. of absolute alcohol containing 30% of hydrogen chloride gas are added while the picrate goes, temporary, into solution. Then the hydrochloride of the vitamin B1 crystallizes. After standing for an hour the vitamin B1 crystals are filtered by suction, washed with 10 ccm. of absolute alcohol and dried in vacuo. One obtains about 0.9 gram vitamin B1 melting at 248.

What we claim is:

l. The preparation of vitamins of the type B1 from a 2',methyl-2.3,dihalogen-tetrahydrofurane which comprises reacting on said compound in an acidic reaction medium with a 2,alkyl-4,amino-5 (thioformamido-alkyl) -pyrimidine.

2. The preparation of vitamins of the type B1 from 2, methyl-2.3, dichloro-tetrahydrofurane, which comprises reacting on said compound in an acidic reaction medium with a 2,methyl-4,amino- 5 (thioformamido-alkyl pyrimidine.

3. The preparation of vitamins of the type B1 from 2,methyl-2.3,dichloro-tetrahydrofurane which comprises reacting on said compound in an acidic medium with 2,methyl-4,amino-5(thioformamido-methyl) pyrimidine.

4. The process as set forth in claim 1, in which the reaction medium is formic acid.

which consists in subjecting Z-methyi- ZB-dichloro-tetrahydrofurane to the action of 2- methyl 4 amino 5-[thioformamido methyl] pyrimidine.

REzso" Korma. ARPAD GERECS. zoLTAN 1 6L131. 

